Necrotising fasciitis is an uncommon soft tissue infection characterised by the widespread necrosis of subcutaneous tissue and fascia, and secondary necrosis of the overlying skin. Ten patients who had necrotising fasciitis were admitted to the intensive care unit of the Prince of Wales Hospital between June 1994 and August 1997. The necrosis in six patients was caused by marine Vibrionaceae. Because of the rapid onset of necrosis, progression to severe disease, and frequently fatal outcome, the public (especially at-risk individuals), general practitioners, and specialist medical personnel should be made aware of the clinical syndrome of necrotising fasciitis caused by marine Vibrionaceae. The diagnosis is dependent on a high index of suspicion, which should be aroused by the presentation of an immunocompromised patient with an extremity lesion and a history of contact with raw seafood or a warm aquatic environment. Once the disease is suspected, treatment should be a course of a third generation cephalosporin, and fluoroquinolone or tetracycline. Aggressive surgical debridement is recommended.